Control for humidifier of the type used with thermostatically controlled furnace

Abstract

A control system for an electrically energized humidifier used with a hot-air furnace including an electric time-delay circuit and control means for manually adjusting the time delay. Each time the thermostat for the system energizes the furnace the humidifier is energized for the predetermined time delay or until the furnace is de-energized, whichever occurs first. The time delay is manually adjusted so that it is longer than the energization cycle of the furnace in warm weather and shorter than the energization cycle of the furnace in cold weather. It is also manually adjusted so that in cold weather at the maximum energization cycle, the humifidier does not produce condensation within the building. The relative humidity of the conditioned air thus decreases proportionately to increases in the atmospheric temperature.

I claim: 
     
       1. A control for use with a humidifier, capable of drawing electrical power from an electrical power source, adapted to be coupled to a hot-air furnace controlled by a thermostat so that moisture is added to heated air leaving said furnace at such time as said humidifier is energized, said thermostat controlling energization of said furnace and providing relatively short furnace operation cycles in warm weather and relatively longer furnace operation cycles in colder weather, said control being connected to said humidifier and to said electrical power source for said humidifier to energize said humidifier for a predetermined continuous period of time within said furnace operation cycle. 
     
     
       2. The control of claim 1 wherein the predetermined continuous period of time is longer than the duration of the shortest furnace operation cycle which occurs when the ambient temperature is above 0 degrees C. and shorter than the duration of the furnace operation cycle that occurs when the ambient temperature is the lowest usually encountered in the geographic area. 
     
     
       3. The control of claim 1 including means for manual adjustment of said predetermined continuous period of time. 
     
     
       4. A heating system for an enclosed volume, comprising: a hot-air furnace having an electrically energized blower capable of drawing power from an electrical power source;   a thermostat for controlling the energization of said furnace and said blower to maintain a setpoint temperature within said enclosed volume, said thermostat being operative to control said furnace and said blower so as to provide relatively short energization cycles when the ambient temperature is relatively high and longer energization cycles when the ambient temperature is relatively low;   an electrically powered humidifier connected to said furnace so that heated air from said furnace passes through said humidifier;   and a control connected to said furnace, said humidifier, and said electrical power source, operative to energize said humidifier for a predetermined continuous period of time starting at the beginning of each furnace energization cycle and to de-energize said humidifier at such time as the predetermined continuous period of time terminates or said furnace is de-energized, whichever occurs first.   
     
     
       5. The system of claim 4 including manually adjustable means for controlling the length of said predetermined time period. 
     
     
       6. A control system for an electrically energized humidifier operative to receive the hot air output of a furnace having a blower, comprising: a timer circuit adapted to measure a predetermined period of time, means for initiating said timer circuit each time said blower is energized, and means for providing electrical power to said humidifier when said energization of said blower begins and terminating electrical power to said humidifier when said energization of said blower stops or said predetermined period of time ends, whichever occurs first.   
     
     
       7. The control system of claim 6, wherein said timer circuit is manually adjustable to control the length of said predetermined period of time. 
     
     
       8. The method of controlling the operation of an electrically energized humidifier of the type used with a furnace having an electrically energized blower comprising: energizing said humidifier each time said blower is energized for a period which does not exceed the time of energization of said blower or a predetermined time period, whichever is shorter.   
     
     
       9. The method of claim 8 including the step of adjusting the predetermined time period to prevent condensation of moisture from humidified air during periods of low ambient temperature. 
     
     
       10. A control system for an electrically energized humidifier operative to receive the hot air output of a furnace having a blower, comprising: a timer circuit adapted to measure a predetermined period of time, means for initiating said timer circuit each time said blower is energized, and means for providing electrical power to said humidifier when said energization of said blower begins and terminating electrical power to said humidifier when said energization of said blower stops or said predetermined period of time ends, whichever occurs first, said timer circuit and said humidifier being electrically in series, said timer circuit being adapted to selectively interrupt electrical power to the humidifier within said predetermined period of time in order to derive its own operating electrical power.   
     
     
       11. A heating system for an enclosed volume, comprising: a hot-air furnace having an electrically energized blower capable of drawing power from an electrical power source;   a thermostat for controlling the energization of said furnace and said blower to maintain a setpoint temperature within said enclosed volume, said thermostat being operative to control said furnace and said blower so as to provide relatively short energization cycles when the ambient temperature is relatively high and longer energization cycles when the ambient temperature is relatively low;   an electrically powered humidifier connected to said furnace so that heated air from said furnace passes through said humidifier;   and a control connected to said furnace, said humidifier, and said electrical power source, comprising:   a timer circuit adapted to measure a predetermined period of time, means for initiating said timer circuit each time said blower is energized, and means for providing electrical power to said humdifier when said energization of said blower begins and terminating electrical power to said humidifier when said energization of said blower stops or said predetermined period of time ends, whichever occurs first, said timer circuit and said humdifier being electrically in series, said timer circuit being adapted to selectively interrupt electrical power to the humdifier before said predetermined period of time ends in order to derive its own operating electrical power.